Nanny - Years ago I was a passenger in a friends car while she was driving. I was telling her about street lights going out. Then I saw up ahead of us, a huge lighted billboard. I told her, watch the lights are going to go out. Sure enough, they went out and came back on after we were past it. She was suddenly very quiet and I think she even stopped breathing for a few seconds. After that she believed anything I told her.
